Alignment film drying system and a method for drying alignment films

ABSTRACT

An alignment film drying system and a method for drying alignment films are proposed. The alignment film drying system is used for drying an alignment film coated on a substrate. The alignment film drying system includes a plurality of magnetrons. The alignment liquid is coated on one side of the substrate facing the plurality of magnetrons and is heated through electromagnetic radiation produced by the plurality of magnetrons. The dried alignment liquid forms an alignment film having a uniform thickness, which ensures that the display effect of LCDs is better.

CROSS-REFERENCES TO RELATED APPLICATION

This application is a divisional application of U.S. application Ser.No. 13/265,868, filed on Oct. 22, 2011 and entitled “Alignment FilmDrying System and a Method for Drying Alignment Films.”

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to liquid crystal displays (LCDs), andmore particularly, to system for drying alignment films and a method fordrying alignment films.

2. Description of the Prior Art

Recently the applications and developments of optoelectronics andsemiconductor technology are increasing. Liquid crystal displays (LCDs)have been widely used in various fields of art. An LCD device comprisestwo glass substrates and a liquid crystal (LC) layer between the twoglass substrates. Among variants of LCDs, thin film transistor liquidcrystal displays (TFT-LCDs) are the mainstream.

TFT-LCD manufacturing processes are mainly divided into three parts: toform patterns on the two glass substrates, to seal LCs to form LC cellsbetween the two glass substrates, and to package the LC cells as aliquid crystal module (LCM).

A plurality of LC cells are disposed on the glass substrates for thepractical process. The number and the position of LC cells disposed onthe substrates vary with the product model and the size of thesubstrates. The plurality of LC cells will form a single LC cell afterLCs are sealed and cut.

While the LCs are sealed between the two glass substrates to form the LCcells, an alignment film is disposed on an LC cell region (or a displayarea, and a non-display area for the other area) of each of the glasssubstrates. After a rubbing process is performed on the alignment film,the alignment film disposed on the display area of the glass substrateleads to the LCs being uniformly arranged in a specific direction.

In the conventional technology, the process for forming the alignmentfilm on the glass substrates comprises the following steps:

(1) Film coating: An alignment film material diluted with a solvent isformed on the surface of the substrates through the use of printingtechnology and so on. The alignment film material commonly used ispolyimide. The solvent commonly used to dilute the alignment filmmaterial comprises N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL),and 2-butoxyethanol (BC).

(2) Drying: The solvent is evaporated at about 100° C. until a uniformalignment film is formed.

(3) Roasting: The alignment film is cured at a temperature above 180° C.

There will be two problems in the step of drying. Referring to FIG. 1, asubstrate 101 is generally placed on a plurality of support pins 102. Aplurality of alignment film coating areas 104 on the substrate 101 areheated by a heat plate 103. The thermal energy from the heat plate 103is conducted to the substrate 101 through convection and thermalradiation, which slows the heating. Besides, the heating method includesheating the substrate 101 and then conducting the thermal energy fromthe substrate 101 to an alignment liquid on the alignment film coatingareas 104, as shown in FIG. 1. So, the problems are that:

(a) In the step of drying, the plurality of alignment film coating areas104 are not uniformly heated from the margins to the center, leading todifferent evaporation rates of the solvent on the plurality of alignmentfilm coating areas 104. Accordingly, the thickness of the margins of thealignment film is not uniform, leading to the alignment ability of themargins of the alignment film differing from that of the center of thealignment film. Finally, the display operates abnormally.

(b) The substrate 101 is not heated uniformly, for the temperature oftouch positions of the plurality of support pins 102 and the substrate101 is different from that of the other area of the substrate 101. Sothe alignment film disposed on the plurality of support pins 102 isinclined to suffer abnormal dryness and have abnormal alignment ability,leading to a bad display quality.

In sum, whether or not the alignment liquid on the plurality ofalignment coatings on the substrate is evenly heated to form analignment film having a uniform thickness and to ensure the displayeffect of LCDs is one of the technical problems in LCD productions.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide analignment film drying system for resolving a problem that the thinknessof an alignment film is not uniform because an alignment liquid is notevenly heated in the conventional technology.

According to the present invention, an alignment film drying system fordrying an alignment liquid coated on a substrate is provided. Thealignment film drying system comprises a plurality of magnetrons. Thealignment liquid is coated on one side of the substrate facing themagnetrons. The alignment liquid is heated through electromagneticradiation produced by the magnetron to form an alignment film.

The alignment film drying system comprises a drying chamber in which theplurality of magnetrons are placed.

The alignment film drying system further comprises a temperature controldevice comprising a thermography for detecting the internal temperatureof the drying chamber, and a thermostat for lowering the temperatureonce the thermography discovers that the internal temperature of thedrying chamber exceeds a threshold for the alignment film drying system.

The drying chamber comprises a delivery wheel inside.

The drying chamber further comprises an entrance and an exit so that thesubstrate is put into or taken out of the drying chamber via theentrance and the exit, the substrate driven by the delivery wheel beingput into the drying chamber via the entrance, being heated throughelectromagnetic radiation produced by the plurality of magnetrons, andthen being taken out of the drying chamber.

In one aspect of the present invention, the alignment film drying systemcomprises a plurality of magnetrons forming a honeycomb-like structure.

In another aspect of the present invention, the alignment film dryingsystem further comprises a gas circulation device comprising an inletpipe and an exhaust pipe, the plurality of magnetrons are placed in agap between the substrate and the inlet pipe, the inlet pipe is used forbeing a passage through which a gas is injected to the drying chamber,the gas flows to the alignment liquid on the substrate after beingheated by the plurality of magnetrons and dries the alignment liquid,and the heated gas is expelled through the exhaust pipe.

It is another object of the present invention to provide an alignmentfilm drying system for resolving a problem that the thinkness of analignment film is not uniform because an alignment liquid is not evenlyheated in the conventional technology.

According to the present invention, an alignment film drying system fordrying an alignment liquid coated on a substrate is proposed. Thealignment film drying system comprises a plurality of magnetrons. Thealignment liquid is coated on one side of the substrate facing themagnetron, and the alignment liquid is heated through electromagneticradiation produced by the magnetron to form an alignment film.

In one aspect of the present invention, the alignment film drying systemcomprises a plurality of magnetrons forming a honeycomb-like structure.

In one aspect of the present invention, the alignment film drying systemfurther comprises a drying chamber in which the plurality of magnetronsare placed.

In one aspect of the present invention, the alignment film drying systemfurther comprises a gas circulation device comprising an inlet pipe andan exhaust pipe, the plurality of magnetrons are placed in a gap betweenthe substrate and the inlet pipe, the inlet pipe is used for being apassage through which a gas is injected to the drying chamber, the gasflows to the alignment liquid on the substrate after being heated by theplurality of magnetrons and dries the alignment liquid, and the heatedgas is expelled through the exhaust pipe.

In one aspect of the present invention, the alignment film drying systemfurther comprises a temperature control device comprising a thermographyand a thermostat;

the thermography is used for detecting the internal temperature of thedrying chamber; and

the thermostat is used for lowering the temperature once thethermography discovers that the internal temperature of the dryingchamber exceeds a threshold for the alignment film drying system.

In one aspect of the present invention, the drying chamber comprises adelivery wheel inside;

the drying chamber further comprises an entrance and an exit so that thesubstrate is put into or taken out of the drying chamber via theentrance and the exit, the substrate driven by the delivery wheel beingput into the drying chamber via the entrance, being heated throughelectromagnetic radiation produced by the plurality of magnetrons, andthen being taken out of the drying chamber.

In one aspect of the present invention, inner walls of the dryingchamber are coated with an electromagnetic radiation absorbing material;

the drying chamber comprises a valve; and

the valve comprises a seal for preventing the electromagnetic radiationinside the drying chamber from leaking outside while the valve isclosed.

It is another object of the present invention to provide a method ofdrying an alignment film for resolving a problem that the thickness ofan alignment film is not uniform because an alignment liquid is notevenly heated in the conventional technology.

According to the present invention, a method of drying an alignment filmcomprising:

putting a substrate coating alignment liquid into a drying chamber via avalve of the drying chamber and closing the valve;

heating the alignment liquid by electromagnetic radiation produced bymagnetrons; and

taking out the substrate from the drying chamber via the opened valveafter a alignment film is formed by the alignment liquid.

In one aspect of the present invention, the step of heating thealignment liquid by electromagnetic radiation produced by magnetronsfurther comprises:

injecting gas into the drying chamber through a inlet pipe;

drying the alignment liquid through the gas heated by the plurality ofmagnetrons and flowing to the alignment liquid; and

expelling the heated gas through a exhaust pipe.

In one aspect of the present invention, the step of heating thealignment liquid by electromagnetic radiation produced by magnetronsfurther comprises:

detecting an internal temperature of the drying chamber; and

lowering the internal temperature of the drying chamber when thedetected internal temperature over a threshold.

The alignment liquid is directly heated through electromagneticradiation (E-M radiation, EMR) produced by a plurality of magnetrons inthe present invention, which resolving the problem existing in theconventional technology that the thickness of the alignment film is notuniform because the alignment liquid is not evenly heated while thethermal energy is conducted from the substrate to the alignment liquid.Moreover, the prevent invention has other benefits: the uniformity ofthe drying effect is not affected, and the heat loss is little,shortening the heating time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of heating alignment liquid coating onalignment film coating areas of a substrate film according to prior art.

FIG. 2 is a schematic diagram of an alignment film drying system isshown according to a first preferred embodiment of the presentinvention.

FIG. 3 is a side view of FIG. 2.

FIG. 4 shows a schematic diagram of the plurality of structurallyarranged magnetrons in the alignment film drying system.

FIG. 5 shows a schematic diagram of an alignment film drying system isshown according to a second preferred embodiment of the presentinvention.

FIG. 6 is a side view of FIG. 5.

FIG. 7 is a flow chart showing an alignment film drying method for LCDsaccording to the first preferred embodiment of the present invention.

FIG. 8 is a flow chart showing an alignment film drying method for LCDsaccording to the second preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

These and other objectives of the claimed invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

An alignment liquid is evenly heated through electromagnetic radiationin the alignment film drying system of the present invention, whichensures that the thickness of the alignment film is uniform and that thedisplay effect of LCDs is better.

Referring to FIG. 2, a schematic diagram of an alignment film dryingsystem is shown according to a first preferred embodiment of the presentinvention.

As shown in FIG. 2, the alignment film drying system comprises aplurality of support pins 202, a plurality of magnetrons 204, a dryingchamber 205, and a gas circulation device. The plurality of support pins202 are used for supporting a substrate 201 on which a plurality ofalignment film coating areas 203 are disposed. The plurality ofalignment film coating areas 203 are coated with an alignment liquidused for forming alignment films. Preferably, the length of theplurality of support pins 202 is determined based on the condition thatthe substrate 201 can be put into or taken out of the drying chamber 205conveniently. As for the number of support pins 202, four support pins202 are used in this embodiment, as shown in FIG. 2. Actually, there isno limit to the number of support pins 202 in the present invention. Inother words, the number of support pins 202 may increase, decrease, orstay the same depending upon practical demands.

As shown in FIG. 2, the plurality of alignment film coating areas 203are disposed on one side of the substrate 201 facing the plurality ofmagnetrons 204. The alignment liquid on the plurality of alignment filmcoating areas 203 is heated through electromagnetic radiation producedby the plurality of magnetrons 204 so as to form the alignment film.Preferably, the electromagnetic radiation produced by the plurality ofmagnetrons 204 includes microwaves; otherwise, other forms ofelectromagnetic radiation are feasible.

Preferably, the alignment film drying system comprises the plurality ofmagnetrons 204. FIG. 4 shows a schematic diagram of the plurality ofstructurally arranged magnetrons 204 in the alignment film dryingsystem. The plurality of magnetrons 204 form a honeycomb-like structureso that electromagnetic radiation produced by the plurality ofmagnetrons 204 can reach the substrate 201 evenly.

As shown in FIG. 2, the plurality of support pins 202 and the pluralityof magnetrons 204 all are placed in the drying chamber 205. Inner wallsof the drying chamber 205 are coated with an electromagnetic radiationabsorbing material such as silicone rubber (SI) used for absorbingunnecessary electromagnetic radiation. In this way, electromagneticradiation will not be reflected back to the plurality of magnetrons 204,preventing causing damage to the plurality of magnetrons 204. Inaddition, the electromagnetic radiation absorbing material coated on theinner wall of the drying chamber 205 precludes microwaves produced bythe plurality of magnetrons 204 from leaking outside.

In the embodiment as shown in FIG. 2, the gas circulation devicecomprises an inlet pipe 206 and an exhaust pipe 207. The inlet pipe 206is a passage through which a gas is injected into the drying chamber205. The plurality of magnetrons 204 are placed in the gap between thesubstrate 201 and the inlet pipe 206. The gas flowing from the inletpipe 206 is heated by the plurality of magnetrons 204. Then, the gasflows to the alignment liquid on the plurality of alignment film coatingareas 203, implementing the drying for the alignment liquid andincreasing the speed of drying the alignment liquid on the substrate201. The exhaust pipe 207 is a passage through which the heated gas isexpelled. The flow of the gas is in the direction of a dotted arrow inFIG. 2.

The alignment film drying system further comprises a temperature controldevice (not shown) which comprises a thermography and a thermostat inthis embodiment. The thermography is used for detecting the internaltemperature of the drying chamber 205 to achieve the best effect ofdrying on the alignment liquid. The temperature of the alignment liquidwill rise too high once electromagnetic radiation is producedexcessively, causing the alignment liquid to boil too fast. Once thethermography discovers that the internal temperature of the dryingchamber 205 exceeds a threshold for the alignment film drying system(e.g., above 180° C.), the thermostat will cool down the drying chamber205. In addition, the internal temperature of the drying chamber 205 canbe lowered by controlling the power of the plurality of magnetrons 204.

The drying chamber 205 is at a temperature range of 80° C.-180° C. where120° C. is the optimal temperature for the practical process.

Referring to FIG. 3, a side view of FIG. 2 is shown.

In the present invention, the drying chamber 205 comprises a valve 208.The location of the valve 208 corresponds to that of the substrate 201so that the substrate 201 can be put into or taken out of the dryingchamber 205 through the valve 208. A seal 209 is mounted on the valve208 and is used for preventing the electromagnetic radiation inside thedrying chamber 205 from leaking outside while the valve 208 is closed.

Referring to FIG. 2 to FIG. 4, the working principle of the firstpreferred embodiment of the present invention is explained as follows:

Referring to FIG. 3, the gas circulation device is switched on for thegas to be injected into the drying chamber 205 through the inlet pipe206 and to be expelled through the exhaust pipe 207. The gas circulationdevice keeps operations.

The valve 208 is opened. The substrate 201 coated with the alignmentliquid is put onto the plurality of support pins 202 by using a roboticarm. Afterwards, the valve 208 is closed. The plurality of magnetrons204 start to operate. The alignment liquid on the substrate 201 isdirectly heated through electromagnetic radiation produced by theplurality of magnetrons 204. Meanwhile, the gas heated by the pluralityof magnetrons 204 flows to the alignment liquid coated on the pluralityof alignment film coating areas 203. The internal temperature of thedrying chamber 205 is detected with the temperature control device. Thepower of the plurality of magnetrons 204 is controlled depending uponthe internal temperature of the drying chamber 205.

After the completely dried alignment liquid on the substrate 201 formsthe alignment film, the plurality of magnetrons 204 stop operating.Then, the valve 208 is opened and the substrate 201 is taken out withthe robotic arm. The drying process for the alignment film on thesubstrate 201 is done. The optimal duration for drying the alignmentfilm is 20-60 seconds.

In this embodiment, the present invention provides the followingbenefits:

(A1) The alignment liquid is directly heated through electromagneticradiation produced by the plurality magnetrons 204, resolving theproblem that the thickness of the alignment film is not uniformresulting from the unevenly heated alignment liquid while the thermalenergy is conducted to the alignment liquid from the substrate 201.

(B1) The alignment liquid is directly heated through electromagneticradiation produced by the plurality magnetrons 204 so that theuniformity of the drying effect on the alignment film from is notaffected by the plurality of support pins 202.

(C1) The alignment liquid is directly heated through electromagneticradiation produced by the plurality magnetrons 204 so the heat loss islittle, improving the heating speed.

Referring to FIG. 5, a schematic diagram of an alignment film dryingsystem is shown according to a second preferred embodiment of thepresent invention.

The alignment film drying system comprises a delivery wheel 501, aplurality of magnetrons 204, a drying chamber 205, and a gas circulationdevice in the embodiment as shown in FIG. 5. The delivery wheel 501 isused for supporting a substrate 201 and for driving the substrate 201 tomove in a horizontal direction. A plurality of alignment film coatingareas 203 on which an alignment liquid is coated are disposed on thesubstrate 201. The alignment liquid is used for forming alignment films.

As shown in FIG. 5, the plurality of alignment film coating areas 203are disposed on one side of the substrate 201 facing the plurality ofmagnetrons 204. The alignment liquid on the plurality of alignment filmcoating areas 203 is heated through electromagnetic radiation producedby the plurality of magnetrons 204 so as to form the alignment film.Preferably, the electromagnetic radiation produced by the plurality ofmagnetrons 204 includes microwaves; otherwise, other forms ofelectromagnetic radiation are feasible.

Preferably, the alignment film drying system comprises the plurality ofmagnetrons 204. FIG. 4 shows a schematic diagram of the plurality ofstructurally arranged magnetrons 204 in the alignment film dryingsystem. The plurality of magnetrons 204 form a honeycomb-like structureso that electromagnetic radiation produced by the plurality ofmagnetrons 204 can reach the substrate 201 evenly.

As shown in FIG. 5, the delivery wheel 501 and the plurality ofmagnetrons 204 both are placed in the drying chamber 205. Inner walls ofthe drying chamber 205 are coated with an electromagnetic radiationabsorbing material such as SI used for absorbing unnecessaryelectromagnetic radiation. In this way, electromagnetic radiation willnot be reflected back to the plurality of magnetrons 204, preventingcausing damage to the plurality of magnetrons 204. In addition, theelectromagnetic radiation absorbing material coated on the inner wall ofthe drying chamber 205 precludes microwaves produced by the plurality ofmagnetrons 204 from leaking outside.

In the embodiment as shown in FIG. 5, the gas circulation devicecomprises an inlet pipe 206 and an exhaust pipe 207. A gas is injectedinto the drying chamber 205 through the inlet pipe 206. The plurality ofmagnetrons 204 are placed in the gap between the substrate 201 and theinlet pipe 206. The gas flowing from the inlet pipe 206 is heated by theplurality of magnetrons 204. Afterwards, the gas flows to the alignmentliquid on the plurality of alignment film coating areas 203,implementing the drying for the alignment liquid on the substrate 201and increasing the speed of drying the alignment liquid on the substrate201. The heated gas is expelled through the exhaust pipe 207. The flowof the gas is in the direction of a dotted arrow in FIG. 5.

The alignment film drying system further comprises a temperature controldevice (not shown) which comprises a thermography and a thermostat inthis embodiment. The thermography is used for detecting the internaltemperature of the drying chamber 205 to achieve the best effect ofdrying on the alignment liquid. The temperature of the alignment liquidwill rise too high once electromagnetic radiation is producedexcessively, causing the alignment liquid to boil too fast. Preferably,the drying chamber 205 is at a temperature range of 80° C.-180° C. where120° C. is the optimal temperature. Once the thermography discovers thatthe internal temperature of the drying chamber 205 exceeds a thresholdfor the alignment film drying system (e.g., above 180° C.), thethermostat will cool down the drying chamber 205. In addition, theinternal temperature of the drying chamber 205 can be lowered bycontrolling the power of the plurality of magnetrons 204.

Referring to FIG. 5 and FIG. 6, the delivery wheel 501 comprises a shaft5011 and a rotary table 5012. The shaft 5011 propels the rotary table5012 to rotate, driving the substrate 201 to move in a horizontaldirection.

As shown in FIG. 5, the drying chamber 205 comprises an entrance 502 andan exit 503 through which the substrate 201 is put into or taken out ofthe drying chamber 205 in this embodiment. The substrate 201 driven bythe delivery wheel 501 is put into the drying chamber 205 via theentrance 502. After being heated through electromagnetic radiationproduced by the plurality of magnetrons 204, the substrate 201 is takenout of the drying chamber 205 via the exit 503.

Referring to FIG. 5 to FIG. 6, the working principle of the secondpreferred embodiment of the present invention is explained as follows:

The gas circulation device is switched on for the gas to be injectedinto the drying chamber 205 through the inlet pipe 206 and to beexpelled through the exhaust pipe 207. The gas circulation device keepsoperations.

The substrate 201 coated with the alignment liquid is put on thedelivery wheel 501 near the entrance 502 with a robotic arm. Afterwards,the substrate 201 driven by the delivery wheel 501 is put into thedrying chamber 205 completely via the entrance 502.

The plurality of magnetrons 204 are turned on and start to operate afterthe substrate 201 is put into the drying chamber 205 completely. Thealignment liquid on the substrate 201 is directly heated throughelectromagnetic radiation produced by the plurality of magnetrons 204.Meanwhile, the gas heated by the plurality of magnetrons 204 flows tothe alignment liquid. The internal temperature of the drying chamber 205is detected with the temperature control device. The power of theplurality of magnetrons 204 is controlled depending upon the internaltemperature of the drying chamber 205.

The alignment liquid on the substrate 201 forms the alignment film afterbeing completely dried. At this time, the plurality of magnetrons 204stop operating, and the delivery wheel 501 starts to operate again. Thesubstrate 201 driven by the delivery wheel 501 is taken out of thedrying chamber 205 via the exit 503.

In this embodiment, the present invention provides the followingbenefits:

(A2) The alignment liquid is directly heated through electromagneticradiation produced by the plurality magnetrons 204, resolving theproblem that the thickness of the alignment film is not uniform becausethe alignment liquid is not evenly heated while the thermal energy isconducted from the substrate 201 to the alignment liquid.

(B2) The alignment liquid is directly heated through electromagneticradiation produced by the plurality magnetrons 204 so that theuniformity of the drying effect on the alignment film is not affected.

(C2) The alignment liquid is directly heated through electromagneticradiation produced by the plurality magnetrons 204 so the heat loss islittle, improving the heating speed.

FIG. 7 is a flow chart showing an alignment film drying method for LCDsaccording to the first preferred embodiment of the present invention.The alignment film drying method corresponds to the schematic diagram ofthe alignment film drying system as shown in FIG. 2 and FIG. 3.

In Step S701, the substrate is put into the drying chamber via the valveof the drying chamber and the valve is closed.

The plurality of alignment film coating areas are disposed on thesubstrate and are coated with the alignment liquid used for formingalignment films.

In Step S702, the alignment liquid on the plurality of alignment filmcoating areas is heated through electromagnetic radiation produced bythe plurality of magnetrons.

While the alignment liquid on the plurality of alignment film coatingareas is heated through electromagnetic radiation, the gas is injectedinto the drying chamber through the inlet pipe for the practicalprocess. The gas is heated by the plurality of magnetrons and flows tothe alignment liquid, implementing the drying for the alignment liquid.Finally, the heated gas is expelled through the exhaust pipe.

While the alignment liquid on the plurality of alignment film coatingareas is heated through electromagnetic radiation, the thermographydetects the internal temperature of the drying chamber to prevent thetemperature of the alignment liquid from rising too high for thepractical process. The alignment liquid will not boil too fast in casethat the electromagnetic radiation is produced excessively. Thus, thebest effect of drying on the alignment liquid is achieved.

Once the thermography discovers that the internal temperature of thedrying chamber exceeds a threshold for the alignment film drying system(e.g., above 180° C.), the thermostat will cool down the drying chamber.Also, the internal temperature of the drying chamber can be lowered bycontrolling the power of the plurality of magnetrons.

In Step S703, the substrate is taken out of the drying chamber via theopened valve after the alignment liquid forms the alignment film.

FIG. 8 is a flow chart showing an alignment film drying method for LCDsaccording to the second preferred embodiment of the present invention.The alignment film drying method corresponds to the schematic diagram ofthe alignment film drying system as shown in FIG. 5 and FIG. 6.

In Step S801, the substrate is put on the delivery wheel of the dryingchamber via the entrance of the drying chamber.

The plurality of alignment film coating areas are disposed on thesubstrate and are coated with the alignment liquid used for formingalignment films.

In Step S802, the substrate driven by the delivery wheel is transferredinto the drying chamber.

In Step S803, the alignment liquid is heated through electromagneticradiation produced by the plurality of magnetrons in the drying chamber.

While the alignment liquid on the plurality of alignment film coatingareas is heated through electromagnetic radiation, the gas is injectedinto the drying chamber through the inlet pipe for the practicalprocess. The gas is heated by the plurality of magnetrons and flows tothe alignment liquid, implementing the drying for the alignment liquid.The heated gas is expelled through the exhaust pipe.

While the alignment liquid on the plurality of alignment film coatingareas is heated through electromagnetic radiation, the thermographydetects the internal temperature of the drying chamber to prevent thetemperature of the alignment liquid from rising too high for thepractical process. The alignment liquid will not boil too fast in casethat the electromagnetic radiation is produced excessively. Thus, thebest effect of drying on the alignment liquid is achieved.

Once the thermography discovers that the internal temperature of thedrying chamber exceeds a threshold for the alignment film drying system(e.g., above 180° C.), the thermostat will cool down the drying chamber.Furthermore, the internal temperature of the drying chamber 205 can belowered by controlling the power of the plurality of magnetrons 204.

In Step S804, the substrate driven by the delivery wheel is taken out ofthe drying chamber after the alignment liquid finishes being heated bythe plurality of magnetrons.

In contrast to prior art, the alignment liquid is directly heatedthrough electromagnetic radiation produced by the plurality ofmagnetrons in the present invention, which resolving the problem thatthe thickness of the alignment film is not uniform because the alignmentliquid is not evenly heated while the thermal energy is conducted to thealignment liquid from the substrate. Also, the uniformity of the dryingeffect on the alignment film is not affected by the plurality of supportpins, and the heat loss is little, shortening the heating time.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device may be made while retainingthe teachings of the invention. Accordingly, the above disclosure shouldbe construed as limited only by the metes and bounds of the appendedclaims.

What is claimed is:
 1. A method of drying an alignment filmcharacterized in that the method comprising: putting a substrate coatingalignment liquid into a drying chamber via a valve of the drying chamberand closing the valve; heating the alignment liquid by electromagneticradiation produced by magnetrons; and taking out the substrate from thedrying chamber via the opened valve after a alignment film is formed bythe alignment liquid.
 2. The method of drying an alignment film of claim1, characterized in that the step of heating the alignment liquid byelectromagnetic radiation produced by magnetrons further comprises:injecting gas into the drying chamber through a inlet pipe; drying thealignment liquid through the gas heated by the plurality of magnetronsand flowing to the alignment liquid; and expelling the heated gasthrough a exhaust pipe.
 3. The method of drying an alignment film ofclaim 1, characterized in that the step of heating the alignment liquidby electromagnetic radiation produced by magnetrons further comprises:detecting an internal temperature of the drying chamber; and loweringthe internal temperature of the drying chamber when the detectedinternal temperature over a threshold.